She may be one of the youngest faces in frontline politics. She may also have just defeated far more experienced rivals to become the first gay leader elected by the Tories to a national role. Yet Ruth Davidson, the crop-haired former kickboxer and ex-Territorial Army officer, appears to have been under continuous siege since her election as leader of the Scottish Conservative party on 4 November.

It was a bruising contest, and since then, the pummelling has continued.

One of Scotland's most prominent criminal QCs, Paul McBride, lambasted the party as "dysfunctional morons" as he resigned in protest at her victory; she has faced open scorn from one of her main rival's financial backers and seen headlines about internal battles with rivals.

Her main opponent, Murdo Fraser, reportedly refused a frontbench post and took a committee chairmanship instead. There were raised eyebrows at her faltering first performance against Alex Salmond at first minister's questions, on the day of her 33rd birthday. She has yet to score any victories of her own.

She appears to be unfazed. Asked about those attacks, she turns to her chief press adviser and ally, Ramsay Jones, and asks: "How can I be polite about this?" But Davidson sticks to the script; she is well-drilled, focused, and sidesteps awkward questions. She briskly lists the internal reforms she introduced on her election. She abolished the Tories' shadow cabinet and insists on weekly group meetings of all 15 Tory MSPs, introduced weekly conference calls of all senior political figures, and is to unveil two policy commissions, on rural affairs and the economy, this month.

'Fire-tested'

She plans a national membership drive, the party's first in a decade, to address the Tories' greatest problem: their unpopularity in Scotland. The party has "flatlined for decades", she said.

"You know, people will have their opinions but my job is to get on with my job. It's to make the reforms to our party, to our message and to our delivery of the message," she says.

"I'm happy to have debates within the group [and] if that means I take the occasional hit in the newspapers about people disagreeing with me, then fine. I'm big enough to take that hit because actually I think that makes the party stronger and healthier if we fire-tested the arguments that we have."

A current affairs journalist who spent six years with BBC Scotland, often covering the Scottish parliament, she has been likened – to the delight of her backers – to David Cameron. She is young; she faced down two far more experienced and better-known rivals in former Scottish deputy leader Murdo Fraser and Jackson Carlaw, as well as a little-known backbencher, Margaret Mitchell, to win the leadership; and she has that Cameronesque capacity for disarming charm with party activists and for smooth answers.

She disavows the analogies with Cameron but then refers to the similarities: "I would never make a comparison. I hope I'm just Ruth; I'm the one and only Ruth. I don't see myself cut from the mould of anybody else particularly."

Yet, as the risky candidate chosen for her potential not her experience, Davidson repeats the phrases about Cameron which her influential backers, including Scotland's only Tory MP, David Mundell, use to describe her.

"I have said Conservatives never get enough credit for how progressive they can be and how anti-establishment in terms of picking candidates they can be. If you look at, dare I say it, Margaret Thatcher, the leader of a UK party as a woman nearly 40 years ago now, you forget how mould-breaking that was.

"You look at more recent history, David Cameron. Now fair enough you might think he's more of a traditional Tory, but if you look at who he was standing against, look at the field, you're talking about some of the really big beasts of Conservative politics: ex-cabinet ministers, ex-ministers.

"So you've got your Rifkinds, your Ken Clarkes, David Davis had served, Liam Fox had served. And then you've this young guy coming through the pack; people said he'll never [win], how can you possibly get someone so young and so fresh and the rest of it. And yet the party did, because they saw something in him."

That mention of "progressive" is Davidson's only reference to the fact that the Scottish Tories, often associated by critics with intolerant, reactionary politics, have elected, in their first one-member, one-vote contest, a lesbian contender.

It was a non-issue. Not once was her private life – she lives with her partner, Saskia Halcrow, a senior analyst with RBS – used by her opponents in a campaign noted for vicious tactics. Only two members mentioned it during the campaign. The media raise it more.

She plans to maintain a tradition of privacy in Scottish politics. Halcrow did attend Davidson's victory party. "I don't think my partner would be terribly pleased to see too much about herself in literature and won't go very far down that road."

This is about "self-protection" and privacy. "And to be honest, it's about parity. It's not the sort of thing that you would ask straight politicians about."

Despite toying with a political career since her early 20s, Davidson joined the Conservatives only three years ago to stand in the Glasgow North East byelection. She lost, but fought it again in the 2010 election. She was finally elected on the Glasgow regional list last May, after serving for 18 months as chief aide to her predecessor as leader, Annabel Goldie, a redoubtable aunt figure who privately backed Davidson in the leadership contest.

Referendum

After just six months as an MSP, Davidson became the first Scottish Tory leader elected to represent the entire party and elected by the members: 2,983 of the 5,676 voted for her. This, say her officials, gives her the strongest mandate of any Scottish leader.

"I'm a Scot but I'm British too, and I don't want Alex Salmond to take that away from me and I know I'm not alone in this. Judging by the current polls, it's easily two-thirds, one-third in my favour and Alex Salmond has a lot of work to do.

"A broad organisation similar to the 'No to AV' campaign, which encompasses people from all of the unionist parties and of no party, from civic Scotland, from people who believe in the United Kingdom, absolutely can defeat Alex Salmond. Because the numbers are there and because the arguments are on our side."